نتایج جستجو برای: expanded porphyrins

تعداد نتایج: 64232  

Journal: :Zeitschrift fur Naturforschung. C, Journal of biosciences 2004
Kristin Ramberg Thor Bernt Melø Anders Johnsson

Porphyrins are known to be efficient photosensitizer molecules and the combined action of light and porphyrins in Propionibacterium acnes have a lethal action on the cells. Identification and quantification of in situ porphyrins in P. acnes have been done using an integrating sphere connected to an ordinary absorption spectrophotometer, and the amounts of porphyrins in the cells were quantified...

2013
Xiangdong Feng Mathias O. Senge

Functionalized asymmetric porphyrins bearing highly reactive centers in substituents at the mesopositions were synthesized in good yields by the reaction of 5,15-diphenylporphyrin with organolithium reagents. Using these porphyrins as precursors highly complex tetrapyrrolic systems are accessible. The synthetic strategy is based on our earlier reports on the combined use of organolithium and al...

Journal: :Nature 1976

Journal: :Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 2004
Rafael Mateo Gloria Castells Andy J Green Carlo Godoy Carles Cristòfol

Methods developed for porphyrin analysis have low recoveries and/or poor precision for the less polar protoporphyrin IX. We describe a simple method of analysis of porphyrins and biliverdin in bile and excreta of birds based on extraction with HCl 3N: acetonitrile and HPLC/UV analyses. Recoveries were good for protoporphyrin IX and other porphyrins (>79%). Applications of this method showed tha...

Journal: :Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas 1999
S G Afonso R Enríquez de Salamanca A M Batlle

Porphyrias are a family of inherited diseases, each associated with a partial defect in one of the enzymes of the heme biosynthetic pathway. In six of the eight porphyrias described, the main clinical manifestation is skin photosensitivity brought about by the action of light on porphyrins, which are deposited in the upper epidermal layer of the skin. Porphyrins absorb light energy intensively ...

Journal: :Molecules 2015
Ambrish Singh Yuanhua Lin Mumtaz A Quraishi Lukman O Olasunkanmi Omolola E Fayemi Yesudass Sasikumar Baskar Ramaganthan Indra Bahadur Ime B Obot Abolanle S Adekunle Mwadham M Kabanda Eno E Ebenso

The inhibition of the corrosion of N80 steel in 3.5 wt. % NaCl solution saturated with CO2 by four porphyrins, namely 5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphyrin (HPTB), 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphyrin (T4PP), 4,4',4″,4‴-(porphyrin-5,10,15,20-tetrayl)tetrakis(benzoic acid) (THP) and 5,10,15,20-tetraphenyl-21H,23H-porphyrin (TPP) was studied using electrochemical impedan...

2013
GAURI D BAJJU NARINDER SINGH

The synthesis and characterization of new meso-substituted and -substituted unsymmetrical metallorphyrins has been described. A new modified Alder method was used for the synthesis of unsymmetrical porphyrins. Reaction of these unsymmetrical porphyrins with metal chlorides and nitrates afforded the corresponding metalloporphyrins in high yields with excellent purity. These porphyrins and their...

Journal: :Chemical science 2015
Toru Aoki Hayato Sakai Kei Ohkubo Tomo Sakanoue Taishi Takenobu Shunichi Fukuzumi Taku Hasobe

Charge-transfer (CT) π-complexes are formed between planar porphyrins and 1,4,5,8,9,12-hexaazatriphenylene (HAT) derivatives with large formation constants (e.g., 104 M-1), exhibiting broad CT absorption bands. The unusually large formation constants result from close face-to-face contact between two planar π-planes of porphyrins and HAT derivatives. The redox potentials of porphyrins and HAT d...

Journal: :Clinical chemistry 1967
C R Scott R F Labbe J Nutter

A procedure has been developed for the assay of urinary porphyrins. Total porphyrins are extracted from acidified urine into n-butanol. The fluorescence of this solution under ultraviolet illumination gives a preliminary indication of abnormal levels of porphyrins. They are then separated and identified by thin-layer chromatography. Uroporphyrin and coproporphyrin can be qualitatively estimated...

Journal: :Organic & biomolecular chemistry 2015
Chihiro Maeda Kosuke Kurihara Motoki Masuda Naoki Yoshioka

The synthesis and photophysical properties of cyano and ethynyl substituted carbazole-based porphyrins were investigated. The introduction of ethynyl groups induced red shifts, while that of cyano groups induced blue shifts of their absorption bands, which was supported by MO calculations. Ethylenedioxy-appended porphyrins were also prepared via a coupling reaction. The conjugated and electroni...

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